Allow fpdsRequest class to be callable

• Enables the fpdsRequest class to be callable (this was functionality that was enabled in v1.0.0, but was removed in v1.3.0 by accident). Prevents the fpds parse command from failing

Thanks to @vdavez for the catch!

Support for asynchronous API requests and XML multiprocessing

• Makes async API calls using asyncio/aiohttp structure, thus removing dependency on external requests library
• Fixes additional type issues within core library
• Restructures utilities/params.py and its references in the CLI
• Adds support for FPDS ATOM feed v1.5.3 (i.e. all advanced filters supported in fpds.gov are supported with this library)
• Moves PyPI packaging to pyproject.toml

v1.2.1

Addresses a bug where requests with less than 20 records were being truncated since the last ATOM feed request was being truncated at 10 records.

1.2.0

• Includes award_type field to delineate an award as either AWARD or an IDV.
• Provides a more explicit key name convetion for JSON data to prevent overwriting of duplicate fields (i.e. PIID). This was observed in cases when an award has a referenced IDV value.
• More object-oriented programming by creating child classes to better represent XML objects.